<html>
<head>
        <script src="https://unpkg.com/vue/dist/vue.js"></script>
</head>
<body>

<div id="app-4">
  <ol>
   <li v-for="todo in todos">
     {{todo.text}}
   </li>
 </ol>
</div>
<script>
var app4 = new Vue({
  el: '#app-4',
  data: {
    todos: [
      { text: '学习 JavaScript' },
      { text: '学习 Vue' },
      { text: '整个牛项目' }
    ]
  }
})
</script>
<div id="app-3">
  <p v-if="seen">现在你看到我了</p>
</div>
var app3 = new Vue({
  el: '#app-3',
  data: {
    seen: true
  }
})
      
        